1 /* 2 * linux/arch/i386/kernel/head32.c -- prepare to run common code 3 * 4 * Copyright (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE 5 * Copyright (C) 2007 Eric Biederman <ebiederm@xmission.com> 6 */ 7 8 #include <linux/init.h> 9 #include <linux/start_kernel.h> 10 #include <linux/mm.h> 11 #include <linux/memblock.h> 12 13 #include <asm/desc.h> 14 #include <asm/setup.h> 15 #include <asm/sections.h> 16 #include <asm/e820/api.h> 17 #include <asm/page.h> 18 #include <asm/apic.h> 19 #include <asm/io_apic.h> 20 #include <asm/bios_ebda.h> 21 #include <asm/tlbflush.h> 22 #include <asm/bootparam_utils.h> 23 24 static void __init i386_default_early_setup(void) 25 { 26 /* Initialize 32bit specific setup functions */ 27 x86_init.resources.reserve_resources = i386_reserve_resources; 28 x86_init.mpparse.setup_ioapic_ids = setup_ioapic_ids_from_mpc; 29 } 30 31 asmlinkage __visible void __init i386_start_kernel(void) 32 { 33 cr4_init_shadow(); 34 35 idt_setup_early_handler(); 36 37 sanitize_boot_params(&boot_params); 38 39 x86_early_init_platform_quirks(); 40 41 /* Call the subarch specific early setup function */ 42 switch (boot_params.hdr.hardware_subarch) { 43 case X86_SUBARCH_INTEL_MID: 44 x86_intel_mid_early_setup(); 45 break; 46 case X86_SUBARCH_CE4100: 47 x86_ce4100_early_setup(); 48 break; 49 default: 50 i386_default_early_setup(); 51 break; 52 } 53 54 start_kernel(); 55 } 56 57 /* 58 * Initialize page tables. This creates a PDE and a set of page 59 * tables, which are located immediately beyond __brk_base. The variable 60 * _brk_end is set up to point to the first "safe" location. 61 * Mappings are created both at virtual address 0 (identity mapping) 62 * and PAGE_OFFSET for up to _end. 63 * 64 * In PAE mode initial_page_table is statically defined to contain 65 * enough entries to cover the VMSPLIT option (that is the top 1, 2 or 3 66 * entries). The identity mapping is handled by pointing two PGD entries 67 * to the first kernel PMD. Note the upper half of each PMD or PTE are 68 * always zero at this stage. 69 */ 70 void __init mk_early_pgtbl_32(void) 71 { 72 #ifdef __pa 73 #undef __pa 74 #endif 75 #define __pa(x) ((unsigned long)(x) - PAGE_OFFSET) 76 pte_t pte, *ptep; 77 int i; 78 unsigned long *ptr; 79 /* Enough space to fit pagetables for the low memory linear map */ 80 const unsigned long limit = __pa(_end) + 81 (PAGE_TABLE_SIZE(LOWMEM_PAGES) << PAGE_SHIFT); 82 #ifdef CONFIG_X86_PAE 83 pmd_t pl2, *pl2p = (pmd_t *)__pa(initial_pg_pmd); 84 #define SET_PL2(pl2, val) { (pl2).pmd = (val); } 85 #else 86 pgd_t pl2, *pl2p = (pgd_t *)__pa(initial_page_table); 87 #define SET_PL2(pl2, val) { (pl2).pgd = (val); } 88 #endif 89 90 ptep = (pte_t *)__pa(__brk_base); 91 pte.pte = PTE_IDENT_ATTR; 92 93 while ((pte.pte & PTE_PFN_MASK) < limit) { 94 95 SET_PL2(pl2, (unsigned long)ptep | PDE_IDENT_ATTR); 96 *pl2p = pl2; 97 #ifndef CONFIG_X86_PAE 98 /* Kernel PDE entry */ 99 *(pl2p + ((PAGE_OFFSET >> PGDIR_SHIFT))) = pl2; 100 #endif 101 for (i = 0; i < PTRS_PER_PTE; i++) { 102 *ptep = pte; 103 pte.pte += PAGE_SIZE; 104 ptep++; 105 } 106 107 pl2p++; 108 } 109 110 ptr = (unsigned long *)__pa(&max_pfn_mapped); 111 /* Can't use pte_pfn() since it's a call with CONFIG_PARAVIRT */ 112 *ptr = (pte.pte & PTE_PFN_MASK) >> PAGE_SHIFT; 113 114 ptr = (unsigned long *)__pa(&_brk_end); 115 *ptr = (unsigned long)ptep + PAGE_OFFSET; 116 } 117 118